Reciprocating piston machine with a rotary hydraulic displacer between pistons and machine shaft

ABSTRACT

A reciprocating piston machine comprises a housing structure with hydraulic cylinders, piston means reciprocable in said respective cylinders, and a revolvable shaft. A hydraulic displacer mechanism has oil columns in the respective cylinders for linking the displacer mechanism with the pistons, the displacer mechanism comprises a stationary annular portion coaxial with the shaft and forming part of the housing structure. The annular portion has inwardly open chamber recesses distributed along its inner periphery and communicating with the oil columns. The hydraulic displacer mechanism has a rotor diametrically smaller than the interior of the annular housing portion and connected with the shaft in eccentric relation thereto, the rotor is consecutively engageable with the recesses to thereby vary the oil volume in the chambers. A circle of fixed internal gear teeth on the housing structure, meshes with a gearteeth circle on the eccentric rotor. The latter circle has a smaller diameter than the circle of the fixed gear teeth and is in rolling mesh engagement therewith, whereby during operation the rotor sequentially coacts the said respective recesses to form variable volume chambers together therewith.

United States Patent Hartmann et al.

[54] RECIPROCATING PISTON MACHINE WITH A ROTARY HYDRAULIC DISPLACER BETWEEN PISTONS AND MACI'IINE SI'IAFT [72] Inventors: Rudolf Hartmann, Holderlinstr. 4, 6238 l-lofheim; l-Iorst Zimmermann, Am l-lasensprung 16, 6241 Mammolshain, both of Germany [22] Filed: May 12, 1971 [21] Appl. No.: 142,684

[52] US. Cl ..60/54.5 R, 417/390, 418/61 [51] Int. Cl ..F15b 7/00, F04b 9/08, F04b 17/00,

F04b 35/00, F03c 3/00 [58] Field of Search ..4l7/339, 342, 390; 418/61;

[56] References Cited UNITED STATES PATENTS 1,976,040 10/1934 Scott ..417/390 3,224,421 12/1965 Peras ..'...'....418/61X .Primary Examiner-Robert M. Walker Attorney-Curt M. Avery, Arthur E. Wilfond, Hebert L. Lerner and Daniel J. Tick 1 51 Oct. 10,1972

[57] ABSTRACT A reciprocating piston machine comprises a housing structure with hydraulic cylinders, piston means reciprocable in said respective cylinders, and a revolvable shaft. A hydraulic displacer mechanism has oil columns in the respective cylinders for linking the displacer mechanism with the pistons, the displacer mechanism comprises a stationary annular portion coaxial with the shaft and forming part of the housing structure. The annular portion has inwardly open chamber recesses distributed along its inner periphery and communicating with the oil columns. The hydraulic displacer mechanism has a rotor diametrically smaller than the interior of the annular housing portion and connected with the shaft in eccentric relation thereto, the rotor is consecutively engageable with the recesses to thereby vary the oil volume in the chambers. A circle of fixed internal gear teeth on the housing structure, meshes with a gear-teeth circle on the eccentric rotor. The latter circle has a smaller diameter than the circle of the fixed gear teeth and is in 11 Claims, 9 Drawing Figures PATENTED 3.696.614

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RECIPROCATING PISTON MACHINE WITH A ROTARY HYDRAULIC DISPLACER BETWEEN PISTONS AND MACHINE SHAFT Our invention relates to reciprocating piston machines, such as compressors, pumps, engines or motors, in which the forces acting between the reciprocating pistons and the machine shaft are transmitted throughreciprocating oil columns of a hydrostaticdisplacer mechanism.

Machines of this general type are known, for example from the German Pat. Nos- 1,089,589 (Feiss) and 1,179,778 (Krupp). Another reciprocating piston machine with hydrostatic force transmission is described in Philips Technische Rundschau, Vol. 26, pages 346-359. These machines have the disadvantage of requiring an excessive amount of mechanical .components for the hydrostatic displacer transmission, as well as an unsatisfactorily large amount of space. Particularly the machine according to German Pat. No. 1,179,778, requiring a branching of the oil flow, involves using a very large oil volume between the pistons and the hydrostatic displacer mechanism proper.

It is an object of our invention to devise a reciprocating piston machine with a hydraulic displacer mechanism between the pistons and the machineshaft, that avoids the above-mentioned shortcomings of the known machines of this type.

Another object of the'invention is to afford reducing the length of the force transmitting oil columns in order to reduce the flow losses.

Still another object of the invention is to greatly reduce the vibration sensitivity of the working pistons in such machines.

It is also an object to avoid long hydraulic connecting lines between the reciprocating pistons and the displacer mechanism proper so as to correspondingly reduce the space requirements of the machine.

A further object of the invention is to make the performance of the machine, particularly the stroke of the working pistons, virtually invariable, irrespective of changes in oil temperature or compressibility.

To achieve these objects and in accordance with our invention, we provide a reciprocating piston machine between the input or output shaft'and the pistons, with a hydraulic transmission mechanism with a rotating piston, hereinafter briefly called rotor, which has a smaller diameter than the housing portion surrounding the rotor, and is so geared to the stationary housing as to perform a rolling movement which consecutively varies the oil volume in displacer chambers that communicate through the oil columns with the reciprocating pistons.

Preferably suitable according to the invention are rotary or rolling piston displacers with stationary housing of the rolling-piston type with meshing engagement between. rotor and housing and externally situated sealing means, according to Cooley (F. Wankel: Einteilung der Rotationskolbenmaschinen; Bauformenblatt l3 In such machines the variable-volume chambers are fixed relative to the housing, whereby the connection of these chambers with the reciprocating pistons can be realized in a simple manner. Also suitable, in principle,-

are rotary pistonmachines according to Maillard of Fixen which have rotational pistons coact'with the housing by a slip engagement (F. Wankel, Einteilung der Rotationskolbenmaschinen; Bauformblatt 16).

However, the outer contour of the rotational piston in the latter type machines, particularly in coaction with the radial sealing means is less favorable than with Cooley type machines.

In both types of displacer mechanisms, either the rotor itself or an eccentric shaft journalled in the rotor, may be connected with the power input or output shaft of the machine which affords obtaining different transmission ratios between the frequency of the reciprocating pistons and the speed of the shaft. Furthermore, two or more adjacent chambers can be connected with each other and jointly communicate with one and the same reciprocating piston. This offers advantages with respect to the dimensioning of the rotary piston displacer mechanism.

Based upon:

a. the Cooley rotary piston machine, and

b. the Maillard or Fixe'n rotary piston machine there are 2 8 different basic arrangements available. Relative to the number of the variable-volume chambers in the displacer mechanism and the number of the intercommunicating chambers within the machine, these eight basic'arrangements may be given further variations. According to the invention, the following types of machines or combinations are also available:

a. Double-acting differential pistons: The full-circle as well as the circular ring faces of the reciprocating pistons are hydraulically connected with respective rotary piston displacer mechanisms which, however, have different stroke volumes.

b. Double-acting unison stroke pistons: The circular ring faces, having the same size, are hydraulically connected with two mutually opposite chambers of a single rotary piston displacer, or with 180 mutually displaced chambers of two equal-size rotary piston displacers.

c. The drive is effected by having two reciprocating pistons which run in the same cylinder and have respective phase positions displaced, for example relative to each other. Applicable in this manner, for example, is a four-chamber rotary piston displacer in which each two mutually adjacent chambers act upon the two reciprocating pistons of one of the respective cylinders.

d. The drive is effected by two differential pistons acting through a seven-chamber rotary piston displacer. In this case the full-circle face of the differential piston is hydraulically connected with two adjacent chambers, and the circular ring face is connected with a chamber located opposite the just-mentioned two chambers. The remaining chamber may serve for driving auxiliary equipment or may run idle.

The invention will be further described with reference to the accompanying drawings which, by way of example, show embodiments of machines with rotary displacers of the Cooley type, although, as mentioned above, displacers of the Maillard and Fixe'n type are also applicable.

FlG. l is a schematic longitudinal section through a six-cylinder gas compressor.

FIG. 2 is a cross section taken along the line 11-11 in FIG. 1.

FIG. 3 shows schematically a longitudinal section through a six cylinder ship Diesel engine with a rotary piston displacer mechanism whose take-off shaft has a speed reduced in the ratio of 1:5 relative to the reciprocating piston frequency.

FIG. 4 shows schematically a cross section through the rotary piston displacer mechanism of a threecylinder reciprocating machine in which each two adjacent variable-volume chambers are hydraulically connected with one of the respective reciprocating pistons.

FIG. is a longitudinal section through a machine equipped with differential pistons which are hydraulically connected with two rotary piston displacer mechanism.

FIG. 6 shows a machine whose pistons move in unison and are hydraulically connected with opposite chambers of a rotary piston displacer mechanism.

FIG. 7 illustrates a reciprocating piston machine similar to that of FIG. 6 in which, however, each two chambers of the rotary piston displacer communicate with each other.

FIG. 8 is a schematic and sectional view of a machine in which each two reciprocating pistons move in one of the respective cylinders and are 90 phase displaced from each other.

FIG. 9 is a similar sectional view of a machine with differential pistons hydraulically connected with the rotary piston displacer mechanism.

Referring to FIGS. 1 and 2, the illustrated gas compressor comprises a housing structure with cylinders 1 closed at the top by a cover 2 in which the automatic suction valves 3 and pressure valves 4 are arranged. A reciprocating piston 5 glides in each of the cylinders 1 and is rigidly connected by a piston rod 6 with a second piston 7 of smaller diameter which forms part of the hydraulic power transmission. The cylinder space 8 is filled with liquid, preferably oil, which connects the reciprocating piston 7 with a rotary piston (rotor) of the hydraulic displacer mechanism proper. The drive shaft 10 of the compressor is coaxially journalled in the housing structure by means of two bearings located at 100 and 10b. The rotor 9 carries sealing rings 9c which are in gliding engagement with the top face of the housing bottom portion 1c and with an inner portion 12 of the housing structure. The rotor 9 has a series of peripherally distributed lobes 9a, five such lobes being provided in the particular embodiment illustrated. A collar 9b of the rotor 9 extends upwardly and has an external ring of gear teeth 9d so as to form a spur gear. This gear is in meshing engagement with a circle of gear teeth 13 formed in the housing portion 12 and having a larger diameter than the gear-teeth circle of the rotor collar 9b.

During rotation of the shaft 10, its eccentric shaft or journal pin 11 causes the rotor 9 to roll along the gear circle 13. The rotor 9 thus perform a rotating and rolling movement within the space defined by the annular portion lb of the housing structure. The annular portion lb has six recesses 14 distributed along the inner periphery. Sealing ledges 15 are provided between the adjacent chambers as is best apparent from FIG. 2.

During rotation of the drive shaft 10, the meshing engagement between the collar 9c and the geared housing portion lb has the effect that, as the rotor rotates, its individual lobes will consecutively enter into and then withdraw from the recesses 14, thus providing variablevolume chambers. Each of these chambers communicates through one of the hydraulic cylinders 8 with the hydraulic pistons 7 of the six-cylinder compressor.

By virtue of the machine design just described, only the rotation of the rotor cylinder axis about the center axis of the machine housing is transferred by the hydraulic displacer mechanism to the reciprocating pistons. The transmission ratio 1' and the pitch circle diameters d, and d of the gear 9d and 13 are determined by the eccentricity e and the number 2 of the chambers 14.

The following equations apply:

These conditions, with a selected radius r of the sealing ledges 15 and a selected distance of these ledges from the center axis of the machine housing, determine the outer contour of the rotor 9, in the present example an equidistant epizycloid. When the rotor 9 is moved by means of the eccentric 11 while being in meshing engagement at 13 with the housing, the chambers 14 become consecutively larger and smaller, during which operations the sealing ledges 15 do not perform any motion.

FIG. 3 illustrates a reversely scavenged intemal-combustion engine. Each cylinder 21 has slots 22 for admission of the scavenging air and slots 23 for exhausing the waste gasses. A piston 24 glides in cylinder 21 and is connected through a piston rod 25, a hydraulic piston 26 and an oil column 27 with a rotor 28 of the displacer mechanism, substantially in the same manner and as described above with reference to FIGS. and 2. The rotor is connected with a rotationally rigid but radially able component, for example a universal joint (cardanic shaft) 29, with the take-off shaft 30. The connection of the rotary piston 28 with the machine housing 31 is effected, on the one hand, by means of an eccentric 32 arranged between the rotor 28 and the machine housing 31 and, on the other hand, through the gearing 33. As explained above, this type of design has the effect that only the rotation of the rotor about its own center axis is transferred to the machine shaft. The geometric relations are the same as described with reference to FIGS. 1 and 2. Relative to the reciprocating piston frequency f, the number 2 of the chambers and the speed n of the shaft, there applies the relation:

n f (z l The machine according to FIG. 3 has the advantage of affording the selection of any desired step-down ratio between the reciprocating piston frequency and the shaft speed, depending upon the number 2 of the chambers. At a low shaft speed, a (z 1) times larger frequency of the reciprocating pistons is effective which, as described in German Pat. No. 1,179,778, is advantageous for driving a ship propeller.

The machine according to FIG. 3 can be modified by employing, instead of the illustrated reversely scavenged two-stroke cylinder, a design equipped with counter piston cylinders. In this case, it is preferable to provide a further rotary piston displacer mechanism arranged on the opposite side of the machine. The two eccentrics in such a machine are rigidly connected with each other.

FIG. 4 illustrates a cross section through the displacer mechanism of a three-cylinder reciprocating piston machine in which each two mutually adjacent chambers are hydraulically connected with one of the respective reciprocating pistons. The rotor 41 has five lobes and it is geared to the housing 42 by spur-gear engagement (not illustratedin FIG. 4) at a transmission ratio of 6 5. As described, the eccentric shaft 43 for the rotor 41 may be connected with the power input or output shaft. In contrast to the rotary piston displacer, according to FIG. 1, the housing 42 according to FIG. 4 does not have six but only three chambers 44, so that only threesealing ledges 45 are needed. The illustrated machine, compared with a rotary displacer mechanism of a 3 2 ratio, offers the following advantages:

a. The front face of the rotary piston displacer for a given displacer surface of the chamber is reduced.

b. The gearing between rotor and housing has more favorable dimensions and better meshing properties.

c. The diameter d of the eccentric shaft 43 can be given a larger size.

The machine illustrated in FIG. 5 is equipped with differential pistons which are hydraulically connected with two displacer mechanisms of different sizes. The reciprocating pistons 52 glide in respective cylinders 51 and are connected through rods 53 with respective hydraulic pistons 54. The full-circle faces 55 of the pistons 54 are connected through the liquid columns 56 with a first rotor 57. The annular faces 53 are connectedthrough liquid columns 59with a second rotor 60. The rotors 57, 60 and consequently the appertaining eccentrics 61 and 62 are 180 phase displaced from each other. Their respective stroke volumes, correspond to the liquid quantities that are displaced by the respective piston faces 55 and 58 so that a positive constrained connection exists between the reciprocating pistons 52 and the power output shaft 63.

A hydraulic mechanism of the kind just described is favorably applicable to a four-cycle engine. The mass forces of the reciprocating pistons 52 effective during the scavenging stroke in the direction toward the cylinder head, are then braced against the eccentric 62 through the ring faces 58, the liquid columns 59 and the rotor 60.

FIG. 6 shows a machine with two main or working pistons 75 rigidly interconnected to move in unison. A single piston mounted midway between the working pistons forms part of the hydraulic displacer mechanism and has its opposite faces act upon respective oil columns which communicate with the variablevolume chambers of the displacer proper. The connections of the ring faces 71 and 72 with the respective chambers 73 and 74 are displaced 180 from each other without any positive constrained connection between the reciprocating piston 75 and the rotary piston 76 of the displacer mechanism.

FIG. 7 shows the same fundamental principle as FIG. 6, except that each two adjacent chambers are combined to form a single larger chamber 77. The resulting advantages are described above with reference to FIG. 4.

The process cycles of hot-gas engines and of coldproducing machines according to the Stirling method require a processing space whose volume is varied and displaced by two reciprocating pistons phase-displaced relative to each other. These requirements are met by the embodiment illustrated in FIG. 8. A rotary piston 82 coacting with four variable-volume chambers 81 shifts the reciprocating pistons 83 between which the processing space 84 is situated, the pistons 83 operating with a phase difference of 90.

FIG. 9 exemplifies a four-cycleengine with two fourcycle pistons cooperating through a positive hydraulic connection with a single rotary-piston displacer mechanism. The reciprocating main or working pistons 91 are connected by respective piston rods 92 with respective pistons 93'acting upon oil columns. The fullcircle faces 94 act hydraulically upon double chambers 97. The annular faces 95 are'hydraulically connected with single chambers 98. A positive constrained connection is obtained if the stroke volume ratio of the chambers 97 and 98 is identicalwith front-face ratio of the piston 93. As described with reference FIG. 3, the rotor 94 may be directly connected with the power take-off shaft, this in the'presentexample, results in a rotorspeedofn=f: (z 1)=f. 6.

Furthermore, two or more of the illustrated twocylinder units can be combined to form a machine having 4, 6, 8 or a higher even number of cylinders.

To those skilled in the art, it will be apparent from the study of this disclosure that our invention permits various modifications and may be given embodiments other than those illustrated and described herein,

without departing from the essential features of our invention and within the scope of the claims annexted hereto.

We claim:

1. A reciprocating piston machine comprising a housing structure with hydraulic cylinders and piston means reciprocable in said respective cylinders, a revolvable shaft, a hydraulic displacer mechanism having oil columns disposed in said respective cylinders and linking said displacer mechanism with said piston means for transferring power through said displacer mechanism between said piston means and said shaft, said displacer mechanism comprising a stationary an nular portion coaxial with said shaft and forming part of said housing structure, said annular portion having inwardly open chamber recesses consecutively distributed along its inner periphery and communicating with said oil columns, a rotor diametrically smaller than the interior of said annular housing portion and connected with said shaft in eccentric relation thereto, said rotor being consecutively engageable with said recesses to thereby vary the oil volume in said chambers, a circle of fixed internal gear teeth on said housing structure, said eccentric rotor having an external gear-teeth circle of smaller diameter than said circle of fixed gear teeth and in rolling mesh engagement therewith, whereby during operation said rotor sequentially coacts with saidrespective recesses to form variable volume chambers together therewith.

2. In a machine according to claim 1, said rotor having peripherally distributed lobes consecutively engageable into said stationary recesses for varying the volume of said chambers during rolling motion of said eccentric motor.

3. In a machine according to claim 1, said housing structure comprising main cylinders coaxially aligned with said respective hydraulic cylinders, working pistons reciprocable in said respective main cylinders, said hydraulic piston means being fixedly joined with said working pistons to reciprocate together therewith.

4. A machine according to claim 1, comprising an eccentric shaft about which said rotor is rotatable, said eccentric shaft being integrally joined with said machine shaft.

5. In a machine according to claim 1, said rotor being stationally fixed but radially movable relative to said machine shaft.

6. In a machine according to claim 1, a plurality of adjacent ones of said recesses being connected with one of said respective hydraulic piston means.

7. A machine according to claim 1, comprising a second displacer mechanism corresponding to the first mechanism but of different size, said two displacer mechanisms having respective eccentrics rigidly joined with each other and with said shaft so that the rotors of said mechanisms operate in unison, each of said piston means having different face areas on opposite sides respectively to act as differential piston, said two piston areas being hydraulically connected with said respective two displacer mechanisms.

8. A machine according to claim 1, each of said piston means having two opposite faces of the same size hydraulically connected with two mutually opposite ones of said variable-volume chambers.

9. A machine according to claim 1, each of said piston means having two opposite faces of the same size of which each is connected with a plurality of said chambers located diametrically opposite the chambers with which said other face is connected.

10. In a machine according to claim 1, said housing structure comprising a processing space and having two hydraulic cylinders and respective pistons situated on opposite sides of said processing space, said two pistons being hydraulically connected outside of said processing space with respective two chambers of said displacer mechanism.

11. A machine according to claim 1, wherein said piston means comprise at least one differential piston, each of the different-size face areas of said piston being hydraulically connected with at least one of said chambers located diametrically opposite the chamber with which the other face area is connected.

* IR l 0' 

1. A reciprocating piston machine comprising a housing structure with hydraulic cylinders and piston means reciprocable in said respective cylinders, a revolvable shaft, a hydraulic displacer mechanism having oil columns disposed in said respective cylinders and linking said displacer mechanism with said piston means for transferring power through said displacer mechanism between said piston means and said shaft, said displacer mechanism comprising a stationary annular portion coaxial with said shaft and forming part of said housing structure, said annular portion having inwardly open chamber recesses consecutively distributed along its inner periphery and communicating with said oil columns, a rotor diametrically smaller than the interior of said annular housing portion and connected with said shaft in eccentric relation thereto, said rotor being consecutively engageable with said recesses to thereby vary the oil volume in said chambers, a circle of fixed internal gear teeth on said housing structure, said eccentric rotor having an external gear-teeth circle of smaller diameter than said circle of fixed gear teeth and in rolling mesh engagement therewith, whereby during operation said rotor sequentially coacts with said respective recesses to form variable volume chambers together therewith.
 2. In a machine according to claim 1, said rotor having peripherally distributed lobes consecutively engageable into said stationary recesses for varying the volume of said chambers during rolling motion of said eccentric motor.
 3. In a machine according to claim 1, said housing structure comprising main cylinders coaxially aligned with said respective hydraulic cylinders, working pistons reciprocable in said respective main cylinders, said hydraulic piston means being fixedly joined with said working pistons to reciprocate together therewith.
 4. A machine according to claim 1, comprising an eccentric shaft about which said rotor is rotatable, said eccentric shaft being integrally joined with said machine shaft.
 5. In a machine according to claim 1, said rotor being stationally fixed but radially movable relative to said machine shaft.
 6. In a machine according to claim 1, a plurality of adjacent ones of said recesses being connected with one of said respective hydraulic piston means.
 7. A machine according to claim 1, comprising a second displacer mechanism corresponding to the first mechanism but of different size, said two displacer mechanisms having respective eccentrics rigidly joined with each other and with said shaft so that the rotors of said mechanisms operate in unison, each of said piston means having different face areas on opposite sides respectively to act as differential piston, said two piston areas being hydraulically connected with said respective two displacer mechanisms.
 8. A machine according to claim 1, each of said piston means having two opposite faces of the same size hydraulically connected with two mutually opposite ones of said variable-volume chambers.
 9. A machine according to claim 1, each of said piston means having two opposite faces of the same size of which each is connected with a plurality of said chambers located diametrically opposite the chambers with which said other face is connected.
 10. In a machine according to claim 1, said housing structure comprising a processing space and having two hydraulic cylinders and respective pistons situated on opposite sides of said processing space, said two pistons being hydraulically connected outside of said processing space with respective two chambers of said displacer mechanism.
 11. A machine according to claim 1, wherein said piston means comprise at least one differential piston, each of the different-size face areas of said piston being hydraulically connected with at least one of said chambers located diametrically opposite the chamber with which the other face area is connected. 